Magnetic tape cartridge drive with automatic loading

ABSTRACT

A cartridge tape drive having a housing with an opening dimensioned to allow endwise insertion of a rectangular cartridge with an access door along a side edge thereof. The cartridge is supported on a stationary support within the housing. The cartridge tape drive is provided with a mechanism which opens the access door, and a mechanism which moves the cartridge laterally within the housing into operative engagement with a magnetic head. The magnetic head is attached to the stationary support.

RELATED APPLICATIONS

This application is a continuation application of prior application Ser.No. 07/934,045, filed on Aug. 21, 1992, now abandoned, which is adivisional application of prior application Ser. No. 07/433,700, filedNov. 9, 1989 now abandoned. In addition, co-pending divisionalapplication Ser. No. 07/851,718, filed Mar. 16, 1992 now U.S. Pat. No.5,204,792, and continuation-in-part application Ser. No. 07/858,479, nowabandoned, filed Mar. 27, 1992, all claim priority from the same priorapplication Ser. No. 07/433,700, filed Nov. 9, 1989.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a cartridge tape drive, and moreparticularly, to a cartridge tape drive in which a rectangular tapecartridge can be inserted endwise.

2. Description of Related Art

Because of technological innovations relating to small business andpersonal computers, such computers are becoming increasingly easy to usein an ever expanding number of applications. Improvements in technologyhave dramatically increased the speed and capacity of these smallcomputers while simultaneously decreasing the cost of producing them.All of these factors, in combination with many others, have fueled awidespread public demand for smaller more powerful computers.

However, the advantages afforded by the increased speed and capacity ofsmall business and personal computers can only be fully realized ifthere are corresponding improvements in the peripheral equipmentassociated with such computers. One area of particular concern is thatof data storage and backup. The capacity of a typical computer'sinternal data storage system, typically a hard disk, has increaseddramatically. Although there have been improvements in the reliabilityand capacity of traditional floppy disks, when compared to the internalstorage capacity of many small business and personal computers, floppydisks are extremely limited. Accordingly, in order to maintain duplicateor backup copies of the internal memory it is frequently necessary touse a large number of floppy disks. This is both inefficient andinconvenient for the operator.

As a result, there is a demand for a reliable and efficient means ofstoring large amounts of data which can be quickly and convenientlytransferred to or from the internal memory of a computer or some otherdata storage device. A magnetic tape cartridge such as the standardone-quarter inch tape cartridge defined by the industry standard ANSIX3.55-1977 is well suited as such a storage device. An example of such atape cartridge is the DC300XL cartridge manufactured by Minnesota Miningand Manufacturing and described in U.S. Pat. No. 3,692,255. The ANSIcartridge measures approximately six inches in length and four inches inwidth. Further, the cartridge has a pivoting access door along one ofits longitudinal edges which must be swung open to allow access to themagnetic tape within the cartridge. With the door fully open, the widthof the cartridge is increased to approximately five and three-quarterinches.

This creates a problem because the industry standard for a five andone-quarter inch floppy disk drive requires that the drive fit within arectangular box measuring three and one-quarter inches in height, fiveand three-quarter inches in width, and eight inches in length. Thisstandard is referred to hereafter as the form factor or the five andone-quarter inch form factor. Additionally, a half-height form factorhaving a height of one and five-eighths inches with the same width andlength is increasingly popular. As can be appreciated the width of thecartridge with the access door fully opened is approximately the same asthe width of the form factors. This makes it extremely difficult todesign a tape drive which will allow use of the cartridge and still fitwithin the form factors established by the industry.

Existing small business and personal computers are designed inaccordance with the industry form factors. As a result, the cabinets ofsuch computers cannot readily accommodate drives having dimensionslarger than the form factors. Further, consumers are accustomed to theexisting form factors and because of their desire for smaller morecompact computers are unlikely to accept an increase in the size ofdrives. As a result, there is a need for a tape drive for the cartridgethat is capable of fitting within the five and one-quarter inch formfactor or the half height form factor.

Typically, when a drive is mounted within a computer cabinet only thefront of the drive is accessible. The front of the drive measures fiveand three-quarters inches across and either three and one-quarter inchesor one and five-eighths inches high, depending on whether the cabinet isdesigned in accordance with the full height or half height form factor.As a result, it is difficult for the cartridge which is approximatelysix inches in length to be inserted edgewise through the front of thedrive.

Accordingly, one drive which is designed to use the cartridge has adrawer-like design. That is, the drive is designed to slide out of thecabinet like a drawer. This provides access to the side of the drive andallows edgewise insertion of the cartridge into the side of the drive.However, such a system requires a large number of moving parts which aresubject to failure. Further, when the drive is slid out from thecabinet, sensitive elements of the drive may be exposed to damage orcontamination which may impair the performance of the drive.Additionally, the sliding drive requires specially designed electricalbusses or connectors which are likely to wear and possibly fail withextended use.

In an attempt to alleviate the problems associated with the slidingdrive, another drive designed for use with the cartridge employs astationary housing. The cartridge is inserted endwise through the frontof the drive. In this drive, a slidable tray extends partially out ofthe front of the drive. The cartridge is placed on the tray and manuallypushed into the drive. As the cartridge and tray are being pushed intothe drive a telescoping, pivoting, spring loaded arm partially opens thecartridge access door to expose the tape. The magnetic head of the tapedrive is mounted on a pivoting frame within the drive. When the tray andcartridge are in place within the drive, a lever situated on the frontof the drive is rotated to pivot the frame, bringing the magnetic headinto contact with the tape.

This drive contains a large number of moving parts which are subject towear and prone to fail. Further, as with the drawer-like drive, theelectrical connections to the head and other elements mounted on thepivoting frame typically are designed to allow for movement as the frameis pivoted. As a result, they are subject to wear and failure.

Additionally, it is difficult to ensure precise and reliable positioningof the head with respect to the cartridge. This is because the cartridgeis located on a sliding tray and the head is mounted to a pivotingframe. Because both elements are movable there is likely some playbetween the head and the tape. This problem is exacerbated as theelements of the drive wear during normal use. As a result of thedifficulty in maintaining a consistent and precise relationship betweenthe tape and the head, there is an increased likelihood of errorsoccurring as data is transferred to or from the tape. As the trackdensity of tapes is increased, tolerances are decreased and it isincreasingly important to ensure the proper and consistent location ofthe tape with respect to the head.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide acompact cartridge tape drive which accommodates the endwise insertion ofa rectangular cartridge having an access door along a side longitudinaledge thereof which must be opened to provide access to the tape withinthe cartridge.

A further object of the invention is to provide a cartridge tape drivewhich allows for the precise and repeatable positioning of the tape withrespect to the head.

Another object of the invention is to provide a cartridge tape drivewhich has an uncomplicated structure, is reliable, easy to manufacture,and simple to operate.

In accordance with these and other objects, a cartridge tape drive inaccordance with a preferred embodiment of the present invention has ahousing with an opening dimensioned to allow endwise insertion of arectangular cartridge having an access door along a side edge thereof.The cartridge is supported on a stationary support within the housing.The cartridge tape drive is provided with a mechanism which opens theaccess door, and a mechanism which moves the cartridge laterally withinthe housing into operative engagement with a magnetic head. The magnetichead as a result may be attached to a stationary support.

In another aspect of the invention, the cartridge tape drive includes amechanism which allows for manual removal of the cartridge from thedrive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a cartridge tape drive in accordancewith a preferred embodiment of the present invention and a cartridge foruse therein.

FIG. 2 is a top view of the cartridge tape drive of FIG. 1.

FIG. 3 is a bottom view of the cartridge tape drive of FIG. 1.

FIG. 4 is a sectional view taken along line 4--4 in FIG. 2.

FIG. 5 is a partial sectional view similar to FIG. 4 but showing thedetails of the bezel door opening mechanism in the open position.

FIG. 6 is a top view of the cartridge tape drive of FIG. 1 with thecartridge partially inserted and the access door partially open. Aportion of the cartridge is cutaway to show the details of theovertravel mechanism.

FIG. 7 is a bottom view of the cartridge tape drive of FIG. 1 with thecartridge in the same position shown in FIG. 6.

FIG. 8 is a partial sectional view taken along line 8--8 in FIG. 2showing the details of the retractable indexing block in the retractedposition.

FIG. 9 is a partial sectional view similar to FIG. 8 but with thecartridge partially inserted and the retractable indexing block in theengaged position.

FIG. 10 is a partial sectional view taken along line 10--10 in FIG. 6showing the drive motor activation switch.

FIG. 11 is a partial top view of the cartridge tape drive of FIG. 1showing the details of the access door opening mechanism prior toinsertion of the cartridge.

FIG. 12 is a partial sectional view taken along line 12--12 in FIG. 11.

FIG. 13 is a partial top view of the cartridge tape drive of FIG. 1showing the details of the access door opening mechanism with thecartridge partially inserted and the access door partially open.

FIG. 14 is similar to FIG. 13 with the cartridge further inserted andthe access door further open.

FIG. 15 is a top view of the cartridge tape drive of FIG. 1 with thecartridge fully inserted. The cartridge is shown partially cutaway toshow the details of the overtravel mechanism.

FIG. 16 is a bottom view of the cartridge tape drive of FIG. 1 with thecartridge fully inserted. The cartridge is shown partially in phantom.

FIG. 17 is a partial sectional view taken along line 17--17 in FIG. 15showing the details of the bezel door locking mechanism in the lockedposition.

FIG. 18 is a partial sectional view taken along line 18--18 in FIG. 17.

FIG. 19 is a partial sectional view taken along line 19--19 in FIG. 2showing the details of a corner positioning block.

FIG. 20 is a partial sectional view taken along line 20--20 in FIG. 2showing the details of the edge positioning block prior to insertion ofthe cartridge.

FIG. 21 is a partial sectional view taken along line 21--21 in FIG. 15showing the details of the edge positioning block with the cartridgefully inserted.

FIG. 22 shows a top view of a drive mechanism in accordance with analternative embodiment of the present invention.

FIG. 23 is a side view of the drive mechanism of FIG. 22.

FIG. 24 is a top view showing the drive mechanism of FIG. 22 in theengaged position.

FIG. 25 is an enlarged end view of the manual withdrawal button showingthe configuration of the slot.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

A cartridge tape drive in accordance with a preferred embodiment of thepresent invention is indicated in FIG. 1 at reference numeral 30. A tapecartridge for use with the drive 30 is indicated as reference numeral32. The illustrated tape cartridge conforms with ANSI specificationX3.55-1977, and is well known to those skilled in the art.

The cartridge 32 is inserted into the cartridge tape drive 30 through abezel door 65 (FIGS. 1 and 2). While within the cartridge tape drive 30,the cartridge is supported by a stationary support tray 58. Uponinsertion, the cartridge is gripped between indexing block 112 andretractable indexing block 122 which engage indexing notches 44a and44b, respectively (FIGS. 6-10). Indexing block 112 and retractableindexing block 122 are attached to a sliding carriage 70. In thismanner, the cartridge 32 moves on the support tray 58 when the slidingcarriage 70 moves. A door opening mechanism opens an access door 52 ofthe cartridge 32 while the cartridge 32 is within the drive 30 (FIGS.11-14).

A moving mechanism which is activated after the cartridge is within thedrive, moves the sliding carriage 70, and hence the cartridge 32, withinthe drive 30 from a forward position (FIG. 6) to a rear position (FIG.15). The path of the carriage 70 is first rearward toward the back ofthe drive 30 and then laterally toward a side of the drive 30. The pathis defined by the interaction of posts 72 and 98 with slots 74 and 96,respectively (FIGS. 2, 3, 7, and 16). During the lateral movement of thecarriage 70 the cartridge 32 is moved into a position in which amagnetic head 158 engages a portion of a magnetic tape 48 exposed by theopen access door 52 (FIGS. 15 and 16). The details of the cartridge 32and the cartridge tape drive 10 are described below.

As seen in FIG. 1, the cartridge has a metal base plate 34, a top cover36, two end walls 38, a rear side wall 40, and a front side wall 42. Theend walls 38 are inset slightly from the end edge of the base plate 34and the top cover 36. The front and rear ends of the baseplate 34 areeach provided with an indexing notch 44a and 44b, respectively, whichextends from the edge of the base plate 34 inward to the end wall 38.

A pair of spools 46 are rotatably mounted within the cartridge 32. Amagnetic tape 48 is wrapped around the spools 46 with a portionextending between the spools 46. The tape path between the spools 46 isdefined by idler rollers (not shown) such that a portion of the tapebetween the spools 46 extends lengthwise within the cartridge 32slightly behind the front side wall 42. A capstan roller 50, which isaccessible through a cut away portion of the cartridge, drives a drivebelt (not shown) which rotates the spools 46 to move the tape 48 fromone spool to the other.

The cartridge 32 has a cut away portion which receives an access door52. The access door 52 pivots about hinge 54 to allow access to aportion of the magnetic tape 48. The cartridge 32 measures approximatelysix inches in length and four inches in width. With the access door 52fully open, the cartridge 32 measures approximately five andthree-quarter inches in width.

The cartridge tape drive 30 has a housing 56 whose width, height, andlength are such that housing will fit within the industry five andone-quarter inch form factor. In the illustrated embodiment, the housingwill fit within the half height form factor. The housing of theillustrated embodiment includes a support tray 58, side walls 60, and afront wall 62. As used herein, the term "housing" refers to the generalsupport structure and frame of the cartridge tape drive 30 and notnecessarily to any type of enclosure. Similarly, when a component isdescribed as being "within the housing" it means that the item would fitwithin an imaginary box defined by the form factor.

As seen in the illustrated embodiment, the housing 56 will typically beopen and allow free access to the internal components of the drive 30.This is because the drive 30 is typically installed within a cavity in acabinet of a larger computer system. In such an environment the cabinetwill provide a protective enclosure. However, should an enclosure berequired for a particular application of the tape drive it could bereadily fabricated and integrated into the illustrated housing by oneskilled in the art.

As illustrated in FIGS. 1 and 2, the front wall 62 is provided with anopening 64 through which the cartridge 32 can be inserted endwise. Theopening 64 is covered by a bezel door 66 to prevent dust and othercontaminants from entering the drive. As best seen in FIG. 4, the bezeldoor 66 is suspended from a hinge 68 along the top of the opening 64.The hinge 68 is spring loaded so that the bezel door 66 is normallyurged into the closed position. However, the spring force can easily beovercome and the bezel door 66 can be manually opened by inserting thecartridge 32 through the opening 64.

Upon insertion of the cartridge 32 into the drive 30, the base plate 34is received and supported by the upper surface of the stationary supporttray 58. A sliding carriage 70 is provided to move the cartridge 32within the drive 30. As best seen in FIG. 3, the sliding carriage 70 issuspended below the support tray 58. The sliding carriage 70 ismaintained against the lower surface of the support tray 58 by means ofposts 72 which are fixed to the lower surface of the support tray 58,and extend through slots 74 in the carriage. A washer 76 is held inplace on the end of each post 72 by a split ring 78. In this manner thesliding carriage 70 is sandwiched between the support tray 58 and thewashers 76. The distance between the support tray 58 and the washers 76is slightly greater than the thickness of the sliding carriage 70. Thisallows the sliding carriage 70 to slide freely along a path determinedby the shape of the slots 74.

Movement of the sliding carriage 70 is accomplished by means of a drivemechanism, the components of which are best seen in FIGS. 2 and 3. Thedrive mechanism includes a drive motor 80 and a worm gear 82 attached tothe output shaft of the drive motor 80. The worm gear 82 drives a firstreduction gear 84 which drives a second reduction gear 86 which drives athird reduction gear 88. The third reduction gear 88 drives the maindrive gear 90 and an overtravel mechanism 100. The main drive gear 90and the overtravel mechanism 100 are mounted in a recess 92 formed inthe top surface of the support tray 58. The recess 92 is of a depth suchthat the top of the main drive gear 90 and the overtravel mechanism 100are below the top surface of the support tray 58 and do not interferewith the insertion of the cartridge 32.

The main drive gear 90 is provided with an aperture 94 and the supportcarriage 58 is provided with a slot 96 which corresponds to the pathdefined by slots 74 in the sliding carriage 70. A guide post 98 extendsupward from the sliding carriage 70 through the slot 96 and the aperture94 where it is received by the overtravel mechanism 100.

The overtravel mechanism 100 allows for slight disparities in themovement of the sliding carriage 70 and the drive mechanism. Theovertravel mechanism 100 includes two legs 102 and 104 which arepivotably mounted on the center axis of the main drive gear 90. The legs102 and 104 are configured in a manner similar to the two parts of apair of scissors. A spring 106 extends from the short end of leg 102 tothe short end of leg 104 and urges both the short ends and the long endsof the legs together. A post 108 extends upward from the top of the maindrive gear 90 and is received between the long ends of the legs 102 and104.

The post 108 serves two major functions. First, it maintains a slightamount of separation between the long ends of legs 102 and 104, therebydefining a radial slot within which the guide post 98 is received.Second, because the post 108 is fixed to the main drive gear 90, itcauses the overtravel mechanism 102 to rotate as the main drive gear 90rotates. In this manner, the legs 102 and 104 of the overtravel 100 movethe guide post 98, and hence the sliding carriage 70, along the pathdefined by slot 96 as the main drive gear 90 rotates. The action of theposts 72 within the slots 74 helps to assure a smooth uniform movementand prevent binding as the sliding carriage 70 is moved by rotation ofthe main drive gear 90.

As the cartridge 32 is inserted through the opening 64, the base plate34 slides along the top surface of the support tray 58 until the endwall 38 of the cartridge 32 encounters an arm 110. The arm 110 ispivotably mounted on an indexing block 112 which is fixed to the slidingcarriage 70. As the cartridge 32 is pushed further into the drive 30 itpresses against the arm 110 causing it to pivot about axis 114 until thearm 110 is generally parallel to the cartridge end wall 38 as shown inFIG. 6. The end of the arm 110 is provided with a roller 116 whichallows the arm 110 to slide freely along the end wall 38 as the arm 110pivots. The arm 110 is provided with a spring 118 which biases arm 110into a position against a stop 120. In this manner, the arm 110 pushesagainst the end wall 38 to assist in ejecting the cartridge 32 duringthe eject procedure described below.

Upon further insertion of the cartridge 32, indexing block 112 isreceived in cartridge indexing notch 44a. With the indexing block 112received in the indexing notch 44a and abutting the leading edge of thebase plate 34, further insertion of the cartridge 32 requires movementof the sliding carriage 70. However, until the drive motor 80 isactivated it serves as a brake and resists manual movement of the maindrive gear 90.

Nevertheless, the carriage 70 can move slightly as a result of theovertravel mechanism 100. As illustrated in FIG. 6, the sliding carriage70 can be moved slightly by applying pressure to the cartridge 32. Themovement is accomplished by overcoming the force of the overtravelspring 106 to spread the legs 102 and 104 of the overtravel mechanism100. During the slight manual movement of the sliding carriage 70allowed by the overtravel mechanism 100, three events occur.

First, a retractable indexing block 122, seen best in FIGS. 2, 6, 8, and9, moves from its retracted position (FIGS. 2 and 8) to its engagedposition (FIGS. 6 and 9). When the retractable indexing block is in theengaged position, the cartridge is gripped between the retractableindexing block and the indexing block. This allows the cartridge to bemoved by moving the sliding carriage to which the retractable areattached. The retractable indexing block 122 is hingedly mounted to theupper surface of the sliding carriage 70. A spring 124 biases theretractable indexing block 122 upward. A stud 126 extends downward fromthe retractable indexing block 122 through aperture 128 in the slidingcarriage 70. Extending from the front wall 62 below the sliding carriage70 is a block 130. Block 130 is positioned such that when the slidingcarriage 70 is in the forward position, illustrated in FIGS. 2 and 8,the block 130 engages the stud 126 to overcome the force of the spring124 and maintain the retractable indexing block 122 in its retractedposition so as not to obstruct insertion of the cartridge 32. As thesliding carriage 70 moves rearward, the stud 126 moves out of engagementwith the block 130, thereby allowing the retractable indexing block 122to move under the force of spring 124 to the engaged position as shownin FIGS. 6 and 9. In the engaged position, the retractable indexingblock 122 is received by indexing notch 44b.

Another event which occurs during the slight manual movement of thesliding carriage 70 allowed by the overtravel mechanism 100 is theactivation of the drive motor 80. As illustrated in FIG. 10, a switchmechanism 132 is mounted to the side wall 60. Extending upward from theswitch mechanism 132 is a spring loaded switch actuator 134. When thesliding carriage 70 is in the forward position it is directly above theswitch actuator 134, as seen in FIG. 3, and maintains the actuator 134in a depressed position. However, as the sliding carriage 70 movesrearward, it moves away from the switch actuator 134 allowing the springloaded switch actuator 134 to move to a raised position. A ramp 136 isprovided to ensure a smooth transition as the switch actuator 134 movesbetween the depressed position and the raised position.

The movement of the switch actuator 134 from the depressed position tothe raised position activates the drive motor 80, which, as explainedabove, drives the main drive gear 90 to move the sliding carriageinward. Because the cartridge 32 is held firmly between the indexingblock 112 and the retractable indexing block 122, the cartridge 32 ispulled inward with the sliding carriage 70 along a path defined by slots74 and 96. Cutout areas 137 and 139 are provided in the support tray 58to accommodate the indexing block, retractable indexing block, and theaccess door opening mechanism as the sliding carriage moves during theloading process.

As illustrated in FIG. 6, the other event which takes place during theinitial manual movement of the sliding carriage 70 is beginning of theaccess door 52 opening sequence. The access door 52 continues to open asthe cartridge 32 is moved into the tape drive 30 by the drive mechanism.The details of the access door opening sequence are best illustrated inFIGS. 11-14. The access door opening mechanism includes a pivotingmember 138 rotatably mounted on a shaft 140 which extends upward fromthe sliding carriage 70. Shaft 140 is positioned such that it isgenerally coaxial with the hinge 54 of the access door 52 when thecartridge 32 is gripped between the indexing block 112 and theretractable indexing block 122. A spring 146 biases the pivoting member138 in the clockwise (as viewed from the top) direction.

A receiving block 148 having an angled cam surface 150 extends rearwardfrom the front wall 62 below the level of the sliding carriage 70. Astud 142 extends downward from the pivoting member 138 through anarcuate slot 144 provided in the sliding carriage 70 and, when in theforward position (illustrated in FIG. 12), engages an edge of thereceiving block 148. As the carriage 70 moves inward, the stud 142follows the angled cam surface 150, thereby allowing the pivoting member138 to pivot under the force of spring 146. The pivoting member 138 isprovided with a finger 152 which, as the pivoting member 138 pivots,engages the rear extension 154 of the access door 52 to push the accessdoor open. As can be appreciated, the biasing force of spring 146 mustbe greater than that of the spring which maintains the access door 52 inthe closed position.

Initially, the degree to which the pivoting member 138 is allowed topivot, and hence the degree to which the access door 52 is opened, islimited by the engagement of the stud 142 with the angled surface 150.However, as the sliding carriage reaches the position illustrated inFIG. 13, the opening of the access door 52 is limited by the doorcontacting corner positioning block 156. As the access door 52 movesbeyond the corner positioning block 156, the opening of the door by thepivoting member 138 is limited by the engagement of the stud 142 withthe end of the arcuate slot 144 of the sliding carriage 70, as seen bestin FIG. 14. It should be appreciated that it is not necessary for theaccess door to be completely open. Rather, as shown in FIG. 15, theaccess door 52 needs to open only far enough to allow the magnetic head158 to access the magnetic tape 48.

Following activation of the drive motor 80, the main drive gear 90automatically moves the sliding carriage 70, and hence the cartridge 32which is gripped between the indexing block 112 and the retractableindexing block 122, inward along the path defined by slots 74 and 94.Initially this path is straight back toward the rear of the tape drive30. However, as the posts 72 and the guide post 98 follow slots 74 and94, the path of travel curves to move the sliding carriage 58 and thecartridge 32 laterally toward a side of the drive 30. In this manner,the portion of the magnetic tape 48 revealed by the open access door isbrought into contact with the magnetic head 158 and the capstan roller50 is brought into contact with the capstan drive 160. Additionally, thecartridge is correctly positioned with respect to theend-of-tape/beginning-of-tape sensor 162 and the file protect sensor164.

As illustrated in FIG. 15, the final position of the cartridge 32 isdefined by the corner positioning blocks 156 and 166 and the edgepositioning block 168. Each of the corner positioning blocks 156 and 166receives a corner of the base plate 34 and limits movement of thecartridge 32 in the direction of the head 158 or sideways with respectto the head 158. A switch actuator 178 (located directly below andhidden in the drawings by the file protect sensor 164) is positionedsuch that it is depressed by the base plate 34 when the base plate abutsthe inner surface of corner positioning blocks 156 and 166. Depressionof the switch actuator 178 stops the drive motor 80. However, the springforce of the overtravel mechanism 100 biases the cartridge against theinner surface of the corner positioning blocks to ensure accuratepositioning of the cartridge.

As illustrated in FIG. 19, the base of each corner block is providedwith a ball bearing 170 situated within an aperture 172 in the supporttray 58. The ball bearing 170 is seated on a leaf spring 174. Thedistance between the top of the ball bearing 170 and the inside topsurface 176 of the corner positioning block is slightly less than thethickness of the base plate 34. As a result, when the base plate 34enters the corner positioning block the leaf spring 174 flexes andpresses the base plate 34 firmly against top surface 176. In this mannertwo corners of the cartridge are firmly and precisely positioned in apredictable and repeatable manner.

The edge positioning block 168 defines a third positioning point. Asseen in FIGS. 20 and 21, a ball bearing 170a is situated within anaperture 172a and mounted on a leaf spring 174a. A slender rod 180 ispositioned immediately above the leaf spring 174a. As illustrated inFIGS. 6 and 15, the slender rod is received by a pivotably mountedcollar 182 and extends within a recess provided in the support tray fromthe ball bearing 170a to the main drive gear 90. A stud 184 ispositioned on the main drive 90 such that as the cartridge reaches itsfinal position the stud 184 engages one end of the slender rod 180. Thiscauses the slender rod 180 to pivot about collar 182 and moves the otherend of the slender rod from a position adjacent the ball bearing 170a(FIG. 20) to a position beneath the ball bearing 170a (FIG. 21). Thismovement causes the ball bearing 170a to raise and press the base plate34 firmly against the inner top surface 188 of the edge positioningblock. This arrangement advantageously reduces friction and the load onthe drive motor because the base plate 34 is not pressed against surface188 until the cartridge is nearly in its final position.

The two corner positioning blocks 156 and 166 and the edge positioningblock 168 accurately define three precise points, and hence a plane,which determine an accurate and repeatable final position for thecartridge. Further, because the corner positioning blocks 155 and 166,the edge positioning block 168, and the magnetic head 158 are allmounted on the stationary support tray 58, there is no relative movementtherebetween and the accuracy of the position of the cartridge withrespect to the head is greatly enhanced. This accurate relationshipbetween the position of the head and the tape is necessary to ensureproper functioning of the drive during the transfer of information to orfrom the tape.

In the present drive the capstan drive 160, theend-of-tape/beginning-of-tape sensor 162, and the file protect sensor164 are also fixed to the stationary support tray. As a result, theelectrical connections to these elements can be less complex and morereliable than those necessary to connect to movable elements.

It should be noted that this invention is directed mainly to themechanical features of the drive 30. There is no detailed description ofthe function and operation of the capstan drive 160, theend-of-tape/beginning-of-tape sensor 162, and the file protect sensor164. Similarly, there is no detailed description of the logic andcontrol elements associated with the present drive. Further, althoughthe magnetic head is mounted to the support tray in such a manner as toallow the head to be moved between various tracks on the tape, there isno detailed description of the mounting or track adjusting mechanism.This is because these elements are well known to those skilled in theart. Further, the function and operation of these elements may varywidely depending on the desired function of any given drive embodyingthe present invention. However, it should be noted that the space belowthe sliding carriage 70 is designed to receive the necessary circuitryassociated with these elements.

As a precautionary feature to prevent the accidental insertion of asecond cartridge into the drive, the drive is provided with a mechanismwhich locks the bezel door 66 when the sliding carriage is in the rearposition. The mechanism, which is shown best is FIGS. 15-18, includes anelongate member 190 mounted on the support tray 58. The elongate member190 is pivotable about pin 192. A leaf spring 194 is mounted to thebottom of the support tray 58 in engagement with a first end 196 of theelongate member 190. The leaf spring 194 biases the elongate member 190into the plane of the support tray 58.

A post 198 extends from the first end of the elongate member 190 in adirection parallel to and slightly separate from the lower surface ofthe support tray 58. The sliding carriage is provided with a beveledportion 200 positioned to engage the post 198 and urge the first end ofthe elongate member, against the force of the spring 194, away from thelower surface of the support tray. This causes the elongate member 190to pivot about pin 192 such that the second end of the elongate memberis raised from the upper surface of the support tray 58. In the raisedposition, the second end of the elongate member blocks the bezel door 66to prevent a second cartridge from being inserted therethrough.

The process of removing the cartridge from the drive is substantiallythe reverse of the insertion process. To initiate the removal process,the operator presses a button 202 provided of the exterior of the frontwall 62. Pressing the button 202 activates the drive motor 80 in thereverse direction. The drive motor 80 drives the main drive gear 90 inthe reverse direction to reverse the travel path of the sliding carriage58 and the cartridge 32. Immediately following the initiation of theremoval sequence the travel path is substantially in a lateral directionaway from the head 158. During this stage the bezel door 65 is unlockedin the reverse of the locking process described above.

Subsequently, the direction of travel changes and the cartridge is movedendwise toward the bezel door. However, the bezel door only swingsinward. Therefore, the bezel door must be opened before the cartridgereaches it. To facilitate opening of the bezel door, an arm 204,illustrated in FIGS. 4 and 5, is pivotably mounted to pin 206 whichextends from a block 208 (FIG. 3) attached to the underside of thesupport tray 58. A follower 210 is mounted to the arm 204 on one side ofthe pin 206. On the other side of pin 206 the arm extends past the lowerportion of a side edge of the bezel door 66. A pin 212 extends from thearm 204 to engage the outside of the bezel door.

The sliding carriage is provided with a double beveled surface 214 whichis positioned to slide past the follower 210. As the follower 210 slidesalong one incline of the double beveled surface 214, the arm 204 pivotsupward and inward and pin 212 opens the bezel door 66 (FIG. 5). As thefollower 210 slides along the other incline of the double beveledsurface 214, the arm 204 returns to the original position. Typically thecartridge 32 will be beneath the bezel door 66 so that the bezel door 66swings down until it contacts the top cover 36 of the cartridge. Thebezel door 66 swings completely closed when the cartridge is removedfrom the opening 64. The step of opening the bezel door is not necessaryduring the loading sequence because during loading insertion of thecartridge pushes the bezel door open. However, it should be noted thatalthough the door is already open because the cartridge is insertedtherethrough, the action of the arm is the same during insertion of thetape as during removal.

Once the bezel door 66 is open the remainder of the removal sequence issubstantially the reverse of the loading sequence. The access door isclosed, the retractable indexing block is retracted, and the slidingcarriage depresses the switch actuator to deactivate the drive motor 80.Following retraction of the retractable indexing block, spring 118biases arm 110 to eject the cartridge from the drive through the opening64 where it may be retrieved by the operator.

An alternative embodiment of the drive mechanism of the presentinvention is illustrated in FIGS. 22-24. In the alternative embodiment,a spur gear 222 is attached to the output shaft 224 of the drive motor220. Spur gear 222 drives spur gear 226 at a two-to-one reduction inspeed. Spur gear 226, spur gear 228, and worm gear 230 are all fixed toa common shaft 232. Worm gear 230 drives worm gear 234 which rotatesabout shaft 242 and has spur gear 236 affixed thereto. Spur gear 236drives the main drive gear 90 which operates substantially as describedabove.

A bracket 240 mounted to the lower surface of support tray 58 supportsshaft 232 and the lower end of shaft 242. The upper end of shaft 242 isreceived in a recess provided in the lower surface of support tray 58.The support tray 58 is further provided with recesses configured toreceive gear 236 and allow rotation of gears 222, 226, and 224.

The drive mechanism illustrated in FIGS. 22-25 is also provided with amechanism allowing for manual removal of the cartridge from the drive.This feature advantageously allows retrieval of the cartridge from thedrive should the motorized drive mechanism be disabled by a powerfailure or the like. The manual removal mechanism includes a rotatabledrive shaft 244 which extends rearward from the front wall 62 through anaperture in the bracket 240 and is generally coaxial with the outputshaft 224.

The front end of the drive shaft 244 is received within a button 246which is received in an aperture 250 provided in the front wall 62. Thebutton 246 is received within aperture 250 in a manner that allows forboth rotational and longitudinal movement of the button within theaperture. An enlarged ring 258 is provide on the rear end of the button246. The enlarged ring is larger than the aperture 250 and therebyprevents the button 246 from passing completely through the aperture250. The button is further provided with a slot 260 (FIG. 25) whichallows the button to be rotated by means of a screwdriver or the like.

A spur gear 248 is affixed to the rear end of the drive shaft 244. Spurgear 248 is provided with a concentric cavity 262, illustrated inphantom.

Spring 252 is mounted coaxially on the drive shaft. One end of spring252 abuts against bracket 240 and the other against collar 254. Thecollar 254 is positioned on the drive shaft 244 by stop 256 such thatthe spring 252 is slightly compressed. In this manner, spring 252 biasesthe drive shaft 244 toward the front of the drive. Forward movement ofthe drive shaft 244 is limited by reason of the enlarged ring 258abutting the front wall 62.

To operate the manual cartridge removal device a screwdriver or the likeis inserted into slot 260. Axial pressure is applied to the screwdriverto overcome the force of spring 252 and move the drive shaft 244longitudinally inward, to an engaged position as illustrated in FIG. 24.In the engaged position, the end of the output shaft 224 is received incavity 262 and spur gear 248 engages spur gear 228. While in the engagedposition, the cartridge can be removed from the drive by twisting thescrewdriver to turn the drive shaft 244 and spur gear 248. Spur gear 248drives spur gear 228 which is fixed to the same shaft 232 as worm gear230. Worm gear 230 drives drive shaft 244 which is fixed to spur gear236 which drives main drive gear 90 to move the sliding carriage 70 andeject cartridge 32.

In the illustrated embodiment drive shaft 244 drives spur gear 228 witha two to one increase in speed. In this manner, speedy and convenientwithdrawal of the cartridge is facilitated because it is necessary toturn the drive shaft only one-fourth the number of turns that the motormust turn. In order to ensure that the drive shaft is rotated in theproper direction, the slot 260 may be configured with two diametricallyopposed raised quarters 264 with opposing sides 266 of the quarters 264having sloped walls. This well known configuration, illustrated in FIG.25, allows the screwdriver to engage the slot only when it is rotatedthe appropriate direction.

This detailed description is set forth only for purposes of illustratingan example of the present invention and should not be considered tolimit the scope thereof in any way. Clearly numerous additions,substitutions, and other modifications can be made to the inventionwithout departing from the scope thereof. Further, although theillustrated embodiment is designed to use the ANSI X3.55-1977 typecartridge and the illustrated drive is dimensioned to fit within thefive and one-quarter inch form factor, the scope of the inventionincludes drives having a variety of dimensions and designed for use withother types of cartridges. Accordingly, the protection afforded thepresent invention should be limited only by the scope of the appendedclaims and equivalents thereof.

What is claimed is:
 1. In a cartridge tape drive having a read/writetransducer, and a capstan drive mechanism for moving tape past thetransducer and adapted to receive a tape cartridge, a transportmechanism for moving the cartridge within the drive so that the tape ispositioned adjacent to the read/write transducer comprising:a housinghaving at least one side wall, a front wall with a front bezel door anda stationary support tray having a first and second surface, the firstsurface being adapted to receive and support the cartridge in a firstposition wherein said support tray is coupled to said read/writetransducer; a carriage disposed adjacent to the second surface of saidsupport tray; support means for slidably maintaining said carriageadjacent to the second surface of said support tray; means for engagingthe cartridge mounted to said support means; said engaging meanscomprises an indexing block for engaging a leading edge of the cartridgeas the cartridge is inserted endwise into the drive thorough the frontbezel door; means for moving said carriage and the engaged cartridge toa first intermediate position between said first position and a secondposition so that the cartridge is substantially contained in saidhousing and for moving said carriage and the engaged cartridge from saidintermediate position to said second position such that the tape of thecartridge is substantially adjacent to said transducer; overtravel meansfor moving said carriage to a second intermediate position between saidfirst position and said second position as the cartridge is insertedendwise into the drive through the front bezel door; a rotatable post;an overtravel mechanism having a first leg pivotally mounted on a centeraxis; a second leg pivotally cross-mounted to said first leg on thecenter axis, and said over travel mechanism further positioned so thatsaid rotatable post is received between one end of said first and secondlegs thereby forming a radial slot; a drive post affixed to saidcarriage and adapted to receive in said radial slot; a drive post stoppositioned relative to said drive post so as to allow partial movementof said carriage after the cartridge engages said indexing block; springmeans for coupling said first leg to said second leg at an opposite endof said legs to substantially maintain said radial slot during rotationof said rotatable post.
 2. The transport of claim 1 wherein saidovertravel means further comprises a retractable indexing block forengaging a trailing edge of the cartridge as the cartridge is insertedendwise into the drive through said front bezel door.
 3. The retractableindexing block of claim 2 further comprising spring means for biasingsaid retractable indexing block in an engaged position upon insertion ofthe cartridge in the drive.
 4. The retractable indexing block of claim 3further comprising means for maintaining said retractable indexing blockin a retracted non-engaged position when said carriage is at said firstposition.
 5. The transport of claim 1 wherein said moving meanscomprises a main drive gear coupled to said rotatable post and to saidovertravel mechanism and a plurality of slots formed in said carriagethrough which said support means extends whereby said drive post pullsthe carriage along said rotating radial slot upon rotation of said drivegear, said rotatable post and said overtravel mechanism and said supportmeans slides along said plurality of slots.
 6. The transport of claim 5wherein said slots have a first portion substantially parallel to thelength of said housing and a second portion substantially transverse tosaid first portion.
 7. In a cartridge tape drive having a read/writetransducer and a capstan drive mechanism for moving tape past thetransducer and adapted to receive, in an endwise fashion, a rectangulartape cartridge having a tape access door for providing access of theread/write transducer to a length of tape contained in the cartridge, atransport mechanism for moving the cartridge within the drive so thatthe tape is positioned adjacent to the read/write transducercomprising:a housing having at least one side wall, a front wall with afront bezel door and a stationary support tray having a first and secondsurface, the first surface being adapted to receive and support thecartridge; a carriage disposed adjacent to the second surface of saidsupport tray and having a plurality of slots formed therein; supportmeans for slidably maintaining said carriage adjacent to the secondsurface of said support tray; said support means comprises a pluralityof posts and a plurality of washers having a diameter greater than saidpost, each post having one end affixed to said second surface of saidsupport tray and extending through a corresponding one of said slots anda second end attached to a corresponding one of said support washerswhere said carriage is positioned between said second surface and saidwashers; means, affixed to said carriage, for engaging and indexing thecartridge as the cartridge is inserted endwise into the drive throughsaid front bezel door; said engaging and indexing means comprises anindexing block for engaging a leading edge of the cartridge and aretractable indexing block for engaging a trailing edge of the cartridgeas the cartridge is inserted endwise into the drive through said frontbezel door said retractable indexing block being hingedly mounted tosaid carriage; said retractable indexing block further comprising springmeans for biasing said retractable indexing block in an engaged positionupon insertion of the cartridge in the drive; said retractable indexingblock further comprising means for maintaining said indexing block in aretracted non-engaged position when said carriage is at said firstposition; said indexing block further comprising cartridge ejectionmeans for at least partially ejecting the cartridge through the frontbezel door of said housing; said indexing block wherein said ejectionmeans further comprises: an arm having a first end pivotally mounted tosaid indexing block and positioned relative to said indexing block toengage the cartridge at a second end of said arm before said indexingblock engages the cartridge; stop means affixed to said indexing means;and a bias spring for biasing the first end of said arm toward said stopmeans.
 8. The transport of claim 7 wherein said drive means furthercomprising means for opening said front bezel door upon partialinsertion of the cartridge into said housing, for closing and lockingsaid front bezel door as said carriage moves from said first position tosaid second position and for unlocking and opening said front bezel dooras said carriage moves from said second position to said first position.9. The transport of claim 7 wherein said drive means comprises:a maingear, coupled to a drive motor and positioned between said support trayand said carriage, having a post extending toward said support tray; anovertravel mechanism having a first and second leg pivotallycross-mounted on the center axis of said main gear and positioned sothat said post is received between one end of said first and second legsthereby forming a radial slot; means for coupling said first leg to saidsecond leg at an opposite end of said legs to substantially maintainsaid radial slot during rotation of said main gear; a drive post,affixed to said carriage, and received in said radial slot for drivingsaid carriage along a path defined by said plurality of slots uponrotational movement of said main gear and said overtravel mechanism. 10.The transport of claim 9 wherein said overtravel mechanism permitslimited movement of said carriage to a first intermediate positionbetween said first and second position when said drive means isdeactivated and said carriage is in said first position.
 11. Thetransport of claim 10 wherein said activating means comprises aspring-loaded switch actuator maintained by said carriage in anon-activated state by said carriage when said carriage is in said firstposition and in a drive means activating state once said carriage passessaid first intermediate position.
 12. The transport of claim 7 furthercomprising a tape access door opening mechanism pivotally coupled tosaid carriage.
 13. In a cartridge tape drive having a read/writetransducer, and a capstan drive mechanism for moving tape past thetransducer and adapted to receive a tape cartridge, a transportmechanism for moving the cartridge within the drive so that the tape ispositioned adjacent to the read/write transducer comprising:a housinghaving at least one side wall, a front wall with a front bezel door anda stationary support tray having a first and second surface, the firstsurface being adapted to receive and support the cartridge in a firstposition; a carriage disposed adjacent to the second surface of saidsupport tray; support means for slidably maintaining said carriageadjacent to the second surface of said support tray, the cartridgefurther mounted to said support means; means for engaging the cartridge,wherein said engaging means comprises an indexing block for engaging aleading edge of the cartridge as the cartridge is inserted endwise intothe drive through the front bezel door; means for moving said carriageand the engaged cartridge to a first intermediate position between saidfirst position and a second position so that the cartridge issubstantially contained in said housing and for moving said carriage andthe engaged cartridge from said intermediate position to said secondposition such that the tape of the cartridge is substantially adjacentto said transducer; and an overtravel means for moving said carriage toa second intermediate position between said first position and saidfirst position as the cartridge is inserted endwise into the drivethrough the front bezel door, wherein said overtravel means comprises: arotatable post; an overtravel mechanism having a first leg pivotallymounted on a center axis, a second leg pivotally cross-mounted to saidfirst leg on the center axis, and said over travel mechanism furtherpositioned so that said rotatable post is received between one end ofsaid first and second legs thereby forming a radial slot; a drive postaffixed to said carriage and adapted to receive in said radial slot; adrive post stop positioned relative to said drive post so as to allowpartial movement of said carriage after the cartridge engages saidindexing block; spring means for coupling said first leg to said secondleg at an opposite end of said legs to substantially maintain saidradial slot during rotation of said rotatable post.
 14. The transport ofclaim 13 wherein said overtravel means further comprises a retractableindexing block for engaging a trailing edge of the cartridge as thecartridge is inserted endwise into the drive through said front bezeldoor.
 15. The retractable indexing block of claim 14 further comprisingspring means for biasing said retractable indexing block in an engagedposition upon insertion of the cartridge in the drive.
 16. Theretractable indexing block of claim 15 further comprising means formaintaining said retractable indexing block in a retracted non-engagedposition when said carriage is at said first position.
 17. The transportof claim 13 wherein said moving means comprises a main drive gearcoupled to said rotatable post and to said overtravel mechanism and aplurality of slots formed in said carriage through which said supportmeans extends whereby said drive post pulls the carriage along saidrotating radial slot upon rotation of said drive gear, said rotatablepost and said overtravel mechanism and said support means slides alongsaid plurality of slots.
 18. The transport of claim 17 wherein saidslots have a first portion substantially parallel to the length of saidhousing and a second portion substantially transverse to said firstportion.
 19. In a cartridge tape drive having a read/write transducerand a capstan drive mechanism for moving tape past the transducer andadapted to receive, in an endwise fashion, a rectangular tape cartridgehaving a tape access door for providing access of the read/writetransducer to a length of tape contained in the cartridge, a transportmechanism for moving the cartridge within the drive so that the tape ispositioned adjacent to the read/write transducer comprising:a housinghaving at least one side wall, a front wall with a front bezel door anda stationary support tray having a first and second surface, the firstsurface being adapted to receive and support the cartridge; a carriagedisposed adjacent to the second surface of said support tray and havinga plurality of slots formed therein; support means for slidablymaintaining said carriage adjacent to the second surface of said supporttray; means, affixed to said carriage, for engaging and indexing thecartridge as the cartridge is inserted endwise into the drive throughsaid front bezel door, wherein said engaging and indexing meanscomprises an indexing block for engaging a leading edge of the cartridgeand a retractable indexing block for engaging a trailing edge of thecartridge as the cartridge is inserted endwise into the drive throughsaid front bezel door said retractable indexing block being hingedlymounted to said carriage, wherein said indexing block comprises acartridge ejection means for at least partially ejecting the cartridgethrough the front bezel door of said housing, said ejection meanscomprising:an arm having a first end pivotally mounted to said indexingblock and positioned relative to said indexing block to engage thecartridge at a second end of said arm before said indexing block engagesthe cartridge;stop means affixed to said indexing means; and a biasspring for biasing the first end of said arm toward said stop means;drive means for moving said carriage together with the cartridge from afirst to a second position such that the tape is positioned adjacent tothe read/write transducer and for moving said carriage together with thecartridge from said second position to said first position; means foractivating said drive means upon insertion of the cartridge into saidhousing; and means for deactivating said drive means.
 20. The transportof claim 19 wherein said drive means further comprising means foropening said front bezel door upon partial insertion of the cartridgeinto said housing, for closing and locking said front bezel door as saidcarriage moves from said first position to said second position and forunlocking and opening said front bezel door as said carriage moves fromsaid second position to said first position.
 21. The transport of claim19 wherein said drive means comprises:a main gear, coupled to a drivemotor and positioned between said support tray and said carriage, havinga post extending toward said support tray; an overtravel mechanismhaving a first and second leg pivotally cross-mounted on the center axisof said main gear and positioned so that said post is received betweenone end of said first and second legs thereby forming a radial slot;means for coupling said first leg to said second leg at an opposite endof said legs to substantially maintain said radial slot during rotationof said main gear; and a drive post, affixed to said carriage, andreceived in said radial slot for driving said carriage along a pathdefined by said plurality of slots upon rotational movement of said maingear and said overtravel mechanism.
 22. The transport of claim 21wherein said overtravel mechanism permits limited movement of saidcarriage to a first intermediate position between said first and secondposition when said drive means is deactivated and said carriage is insaid first position.
 23. The transport of claim 22 wherein saidactivating means comprises a spring-loaded switch actuator maintained bysaid carriage in a non-activated state by said carriage when saidcarriage is in said first position and in a drive means activating stateonce said carriage passes said first intermediate position.